A low-toxicity drug will be developed to reduce or eliminate the cardiotoxicity associated with cancer chemotherapy with adriamycin. Cardiotoxicity is thought to result from peroxide oxidation of cell wall lipids. Compounds which will be synthesized and studied are dimers of amino carboxy stabilized carbon free radicals. The dimers undergo bond homolysis in solution releasing amino carboxy stabilized carbon free radicals which are scavengers of reactive free radicals and capable of reducing hydrogen peroxide. For the design of an effective drug a structure reactivity relationship for the amino carboxy stabilized radicals will be developed. New electronically and sterically stabilized amino carboxy radicals will be synthesized. Substituents will also be incorporated to achieve water and/or lipid solubility. Radical persistence will be compared with the persistence of our reference system, 5,6-dihydro-3,5,5-trimethyl-1,4-oxazin-2-only radical, by measuring the enthalpy of dissociation and half-life of radical dimers. Reactivity in hydrogen atom transfer will be studied with a variety of potential acceptors especially peroxides and adriamycin. Alpha-amino acid radicals will be synthesized from naturally occurring alpha-amino acids and similarly studied. Amino carboxy stabilized radical dimers will be submitted for biological testing as potential drugs to relieve the cardiotoxicity associated with adriamycin chemotherapy and as anti-cancer agents themselves. Biological activity will be correlated with reactivity in hydrogen atom transfer for the development of an assay for potential activity.